Design Of Greenhouse Plant Physiological And Ecological Wireless Monitoring System Based On WSN

Most greenhouse parameters monitoring systems were built based on CAN bus in manycurrently used greenhouses, in which signals and data were transferred through cables. Thesesystems have some problems. Firstly, cables are always made of metals, so the system has a highercost; secondly, the cable transmission distance is limited, otherwise the attenuation andinterference will lead to failure of system; thirdly, the cables are easily to be eroded, frayed, bittenby insects, and causing to high fault rate in hot and humid environment like greenhouse. To avoidabove problems, this paper proposed a development of a greenhouse parameters monitoring systembased on wireless sensor network, including the design of sensor node and sink node.Wireless sensor networks proposed in this paper was composed of by one sink node and amass of sensor nodes. The main Central Processing Unit (MCU) of all the nodes was adoptedCC2530chip. Many periphery modules were chosen to install on different nodes for differentpurposes. These modules include power module, real time clock module, debugging module, serialcommunications module, sensor module, etc. The personal computer (PC) software of the systemwas designed based on VB platform. The PC software functions include network parameter setting,real-time system status sensing and data storing and query, etc.At the last of this paper, a series of tests and experiments were made to test the system. Thetests included transmission distance test of node and system stability test. During single-nodetransmission distance test, the distance between the sensor node and sink node was increasedgradually from30m to300m. And the sensor node sent1000data packets every10meters. Thenacceptance rate was calculated according to the number of data packets received by the sink node.And the acceptance rate networking transmissions distance test was got in the same way. Thediagram of distance test shows that the acceptance rate is higher than97%when the distancebetween nodes less than100meters, and not lower than90%while the distance is increased to200meters. During system stability test, the system worked without stop from7AM to the next7AM.The sensor node sent1000data packets every half an hour, and the acceptance rate could becalculated every time. The diagram of system stability test shows that the lowest rate is beyond 93%after long time running. Above all, it is proved that the system runs stably and reliably.